Lign. 69. Coral, and Spongites.
Chalk. Sussex.
| Fig. | 1.— | Petalopora pulchella. Upper figure × ×: lower figure, nat. Chalk near Chichester. (Mr. Walter Mantell.) |
| 2.— | Spongites clavellatus. a branch in the cavity of a flint. South Downs. | |
| 3.— | Siphonia Morrisiana. (G. A. M.) A transverse polished section of a pebble. Brighton Beach. |
A smaller ramose spongite, with numerous short clavate protuberances, is often met with in the flints of Sussex and Wilts; a branch is figured in [Lign. 69, fig. 2].[201]
[201] This spongite is named Polypothecia clavellata, in Miss Benett's Wiltshire Fossils.
Spongites Townsendi. (Pict. Atlas, pl. xli.)—The cyathiform flints, whose shape depends on the inclosed zoophytes, so much resemble the cup-shaped sponges of commerce, as to be easily recognized in the heaps of nodules that are collected in chalk districts for the roads; they are from one to eight inches in diameter at the upper part, and many are of a globular or spheroidal shape; the surface has the usual calcareo-siliceous coating of flint nodules, giving a sensation of roughness to the touch; the margin of the cup generally exhibits a narrow band of porous structure, and when broken, sections of the enclosed body are exposed. These funnel-shaped spongites terminate at the bottom in a peduncle, whence fibrous root-like processes diverge; by these appendages the original was fixed to the rock. I have collected a few specimens in which the roots are attached to a shell, or pebble, but have never seen any that appeared to occupy the spot on which they grew. They seem to have been detached from their native sites by the waves, and transported to a distance, and subsiding into the tranquil depths of the ocean, became imbedded in the cretaceous sediments that were accumulating at the bottom.
Spongites (?) labyrinthicus.[202] [Lign. 80, fig. 5.]—Another abundant species of amorphozoa has given rise to sub-hemispherical flints, rounded below and flat above, with a marginal band of porous tissue, that expands into flexuous lobes which fill up the area of the upper surface. When found imbedded in the chalk, the form of this zoophyte is often preserved entire; the upper part showing the lobated and flexuous character of the original. Upon breaking these flints, the organic structure is generally apparent; but in many instances has perished, and left a cavity which is either partially filled with stalactitical chalcedony, or lined with quartz crystals. These fossils vary in size from a walnut to that of an orange; the pedicle has long processes.
[202] Foss, S. D. tab. xv. fig. 7.